Boston’s Back Bay is one of the finest planned 19th century neighborhoods in the world.However within the fabric of its grid and especially at its edges can be found some of the most important mid-century modern architecture in Boston and arguably America.This will be a walking tour that will visit works by many notable 20th century architects including Pietro Belluschi, Paul Rudolph, Hugh Stubbins, Harry Cobb and Araldo Cossutta of I.M. Pei and Partners, Philip Johnson, Charles Gwathmey and Frank Gehry, within a rich context highlighted by the works of, among others, H. H. Richardson and McKim Mead and White.